Many motor vehicles, particularly passenger vans, employ side windows of the type in which a rectangular window pane is mounted within a rectangular window opening by a pair of hinges connecting the top of the window pane with the top of the window opening, and a toggle mechanism acting between the bottom of the window pane and the bottom of the window opening to either clamp the window in a closed position flush with the vehicle body or to swing the bottom of the window pane outwardly to an open position. When the window pane is pivoted outwardly to the open position, the leading edge of the window pane is spaced away from the forward edge of the window opening by a gap which is progressively wider from the top to the bottom of the window.
A shortcoming of the aforedescribed window arrangement is that the outward projection of the window pane interrupts the streamlined airflow over the side of the vehicle body and increases the level of noise within the passenger compartment. Accordingly, it would be desirable to provide a wind deflector for streamlining the vehicle body when the window is in the open position.